[RR16988]

Hello everyone,

I am pretty new to ANSYS Fluent, and I am trying to simulate the flow through a simple De Laval nozzle. The fluid used is air ideal gas at 650 degree C. The nozzle has a subsonic mass-flow inlet and a supersonic pressure-outlet. I seem to have set all the input values right, but for some reason the output contours seem strange. The air is supposed to be accelerated after it passes through the throat of the nozzle. In my simulation, it gets accelerated after the throat, but it then deccelerates after a bit, and then accelerates a bit again, towards the outlet. Does it have something to do with the geometry of my nozzle? Or is it occurring due to some other reason?

Mass flow rate at subsonic inlet = 0.69 kg/s
Inlet pressure = 1000000 Pa
Outlet pressure = 101325 Pa
Inlet temperature = 923.15 K

I am attaching a screenshot of my nozzle model and the strange simulation result that I have got.

NozzlesmoothmodelforCFDonline.jpg

ResultforCFDonline.jpg

[protocol]

Hi

Your model looks like 2d to me did you give axisymmetric condition if not try giving mass flux instead of mass flow rate see if this works and check the boundary condition the flow mainly depends on outlet boundary condition hope this works